1. Technical Field
The present disclosure relates to orthopaedic prostheses and, specifically, to tibial components in a knee prosthesis.
2. Description of the Related Art
Orthopaedic prostheses are commonly utilized to repair and/or replace damaged bone and tissue in the human body. For example, a knee prosthesis may include a tibial baseplate that is affixed to a resected or natural proximal tibia, a femoral component attached to a resected or natural distal femur, and a tibial bearing component coupled with the tibial baseplate and disposed between the tibial baseplate and femoral component. Knee prostheses frequently seek to provide articulation similar to a natural, anatomical articulation of a knee joint, including providing a wide range of flexion.
The tibial insert component, sometimes also referred to as a tibial bearing or meniscal component, is used to provide an appropriate level of friction and contact area at the interface between the femoral component and the tibial bearing component. For a knee prosthesis to provide a sufficient range of flexion with a desirable kinematic motion profile, the tibial bearing component and tibial baseplate must be sized and oriented to interact appropriately with the femoral component of the knee prosthesis throughout the flexion range. Substantial design efforts have been focused on providing a range of prosthesis component sizes and shapes to accommodate the natural variability in bone sizes and shapes in patients with orthopaedic prostheses, while preserving flexion range and desired kinematic motion profile.
In addition to facilitating implantation and providing enhanced kinematics through manipulation of the size and/or geometry of prosthesis components, protection and/or preservation of soft tissues in the natural knee joint is also desirable.
A given prosthetic component design (i.e., a tibial baseplate, tibial bearing component, or femoral component) may be provided to a surgeon as a kit including a variety of different sizes, so that the surgeon may choose an appropriate size intraoperatively and/or on the basis of pre-surgery planning. An individual component may be selected from the kit based upon the surgeon's assessment of fit and kinematics, i.e., how closely the component matches the natural contours of a patient's bone and how smoothly the assembled knee joint prosthesis functions in conjunction with adjacent soft tissues and other anatomical structures. Soft tissue considerations include proper ligament tension and minimization of soft tissue impingement upon prosthetic surfaces, for example.
In addition to prosthetic sizing, the orientation of a prosthetic component on a resected or natural surface of a bone also impacts surgical outcomes. For example, the rotational orientation of a tibial baseplate and tibial bearing component with respect to a resected proximal tibia will affect the interaction between the corresponding femoral prosthesis and the tibial bearing component. The nature and amount of the coverage of a tibial baseplate over specific areas of the resected proximal tibia will also affect the fixation of the implant to the bone. Thus, substantial design efforts have been focused on providing prosthetic components which are appropriately sized for a variety of patient bone sizes and are adapted to be implanted in a particular, proper orientation to achieve desired prosthesis performance characteristics.